The present invention relates generally to signal level indicators and, more particularly, to a method and apparatus for improving the efficiency of signal level indicators.
Consumer demands have fueled technological advances in the area of electronics. Through aggressive development and manufacturing, the industry has accomplished increased miniaturization of electronic components resulting in the advent of extremely lightweight and dimensionally constrained hand held portable electronic devices. Such devices are typically battery powered. The operational longevity of the electronic device based on its associated battery life often becomes the fundamental consumer selling point. In order to maximize battery use and, thus, satisfy consumer demands, these electronic devices must be developed to optimize power consumption without depriving user perceptible functionality.
Consumers often evaluate both the operational features and related user perceptible features of electronic devices prior to purchase. For example, an operational feature of a portable cellular telephone considered by a consumer prior to purchase is the amount of continuous "talk time" or "standby time" permitted by the battery associated with the operation of the portable cellular telephone.
Dependent upon operational features are important user perceptible features, such as the need to display operational data to the user by means of a display having visual elements that may be integrated into the electronic device. For example, the portable cellular telephone is generally equipped to provide users with a visually perceptible indication of the communicative effectiveness of a nearby cellular base station. This is generally accomplished via a bar graph-type of arrangement of visual elements that are sequentially illuminated in accordance with the magnitude or strength of control signals received from the nearby cellular base station. This arrangement of visual display elements is referred to as a signal level indicator or a signal strength indicator.
FIG. 1 illustrates a prior art signal level indicator 100 integrated into an light-emitting diode (LED) display 102. The prior art signal level indicator 100 is comprised of five columns with each column having at least one LED element, such as LEDs 104. The prior art signal level indicator 100 visually displays the proportional strength of received signals by sequentially illuminating the columns of LED elements, beginning with the least significant first column 106 and concluding with the most significant fifth column 108. Thus, the reception of a high-strength signal would result in the illumination of all five columns of LED elements, while a low-strength signal would result in only the illumination of the first column 106. FIG. 1 shows the reception of a medium-strength control signal as evident by the sequential illumination of the first three columns of LED elements (for illustrative purposes, illuminated LEDs are shaded).
Previous signal level indicators, such as that shown in FIG. 1 consume an unacceptable amount of power. The reception of stronger control signals results in the illumination of more LEDs and, thus, greater consumption of battery power. Therefore, what is needed is an apparatus and method for displaying signal levels that consumes minimal power without depriving the user of a clear means of visually perceiving the signal level data. By optimizing the user perceptible features of a portable electronic device, a manufacturer is able to increase the effective life of the battery and, thus, permit longer continuous operation of the device. As a result, the manufacturer is able to produce products that are more attractive to the consumer.